frequency-shift keyed manipulation
«on the whole» coherent reception
S.B. Makarov, A.M. Markov
In this paper the efficacy of «on the whole» coherent reception algorithm of frequency-shift keyed signal sequences with intersymbol interference, a continuous phase and additive white gaussian noise in permanent parameters channel without coding has been studied. As an example, gaussian minimum shift keying (GMSK) signals have been chosen.
The target setting is described and it is paid attention to the application of signals with small values of the spectral bandwidth results in a large energy loss, which may be reduced by «on the whole» reception.
The mathematical formulas for spectral-efficient signals sequences with a continuous phase and the modulation index equal 0,5 has been shown. The requests for the phase function and spectral characteristics of signals have been described.
«On the whole» coherent reception algorithm, based on the Viterbi algorithm of frequency-shift keyed signal sequences, being optimal for normal white noise, has been described. The structural scheme and description of the Viterbi algorithm have been shown. The analysis of bit-error rate for different values of the Bandwidth Time product (BT) was performed and BER curves versus signal-to-noise ratio have been presented. It was determined that the values of the power win for «on the whole» coherent reception algorithm of GMSK signals compared to the coherent elementwise reception algorithm of these signals, being optimal for MSK signals for BT = 0,3 is about 0,25 dB, for BT = 0,25 is 0,5 dB, for BT = 0,2 is 1,5 dB, for BT = 0,15 is 4,5 dB.